Zygoribatula birhanensis, ErmilovK, 2025

ErmilovK, Sergey G., 2025, New species of Oripodoidea (Acari, Oribatidae) from Central Ethiopia, Acarologia 65 (2), pp. 405-416 : 406-410

Zygoribatula birhanensis n. sp.

Zoobank: 3C994735-9F32-40CE-9150-D117BAB1470C

( Figures 1 , 2 )

Type material — Holotype (female) and eight paratypes (three males and five females): Central Ethiopia, Amhara Region, Semien Shewa Zone , 9°51′32.4″N, 39°43′51.2″E, 10 km

NE of Debre Birhan, 2900 m a.s.l., forest with Erica arborea , sifted moss and litter, 24. V.2014 (L.B. Rybalov).

The holotype is deposited in the collection of the Senckenberg Museum of Natural History, Görlitz, Germany ; eight paratypes are in the collection of the University of Tyumen, Museum of Zoology, Tyumen, Russia. All specimens are preserved in 70% solution of ethanol with a drop of glycerol.

Diagnosis — Body length: 420–480. Body surface densely microsculpturing tuberculate; anogenital region slightly foveolate. Rostrum with triangular medial mucro. Lamella with small trapezoid cusp; translamella thin, straight; tutorium present. Sublamellar porose area absent. Rostral, lamellar and interlamellar setae slightly differs in length, long, setiform, barbed; bothridial seta with short stalk and globose, roughened head. Fourteen pairs of short, slightly dilated in median part, barbed setae. Five pairs of rounded notogastral porose areas. Epimeral, aggenital, anal, and adanal setae short, setiform, slightly barbed; all genital setae short, setiform, nearly smooth; leg femora I, II with four setae l″ (absent); genua I, II with two setae (v′ absent).

Description — Measurements. Body length: 465 (holotype), 420–480 (paratypes); notogaster width: 270 (holotype), 255–300 (paratypes). No difference between males and females in body size.

Integument — Body light brown to brown. Surface densely microsculpturing tuberculate

(well observable under low magnification, × 400); additionally, anogenital region with slight sparse foveolae (diameter up to 4).

Prodorsum ( Figs 1 (a, c)) — Rostrum with strongly projecting triangular medial mucro. Lamella about 1/3 length of prodorsum, narrow, with small trapezoid cusp; translamella thin, straight; tutorium developed, ridge-like. Sublamellar porose area absent. Rostral (67–71), lamellar (67–75), interlamellar (60–67), and exobothridial (30–34) setae setiform, barbed; ex thinnest; in erect; bothridial seta (26) with short (7), smooth stalk and globose, roughened head (19). Dorsosejugal porose area slightly observable, oval.

Notogaster ( Figs 1 (a, c), 2(a)) — Anterior margin distinctly convex and rounded medially. Fourteen pairs of setae (15–19) slightly dilated in median part, barbed. Five pairs of rounded porose areas (7–15; sizes vary in specimens, but Aa frequently largest). Opisthonotal gland opening and all lyrifissures well observable.

Gnathosoma ( Figs 2 (b–d)) — Subcapitulum size: 101–105 × 75–82; subcapitular (22–26)

and adoral (13–15) setae setiform, barbed. Palp length: 64–67; setation: 0–2–1–3–9(+ω); postpalpal seta (7) spiniform, nearly smooth. Chelicera length: 116–120; setae cha (: 34; chb:

22) setiform, barbed.

Epimeral and lateral podosomal regions ( Figs 1 (b, c)) — Epimeral formula: 3–1–3–3; all setae (1a, 2a, 3a: 17–19; others: 22–26) setiform, slightly barbed. Humeral porose area Am slightly observable, oval. Discidium not developed. Circumpedal carina short.

Anogenital region ( Figs 1 (b, c), 2(a)) — Anogenital formula: 4–1–2–3; all genital setae (15) setiform, nearly smooth; aggenital (19), anal (15) and adanal (19) setae setiform, slightly barbed. Adanal lyrifissure close and anterior to anal plate. Postanal porose area band-like. Ovipositor typical for Oribatulidae ( Ermilov 2010) ; length of blade: 71; length of distal section (beyond middle fold): 105; width of distal section: 52; each of the three blades with four smooth setae: ψ 1 ≈ τ 1 (37–41) setiform; ψ 2 ≈ τ a ≈ τ b ≈ τ c (11–15) narrowly thorn-like; coronal setae absent.

Legs ( Figs 2 (e–h)) — Median claw thicker than lateral claws; all slightly barbed on dorsal side; each lateral claw with tubercle distoventrally. Proximoventral porose area on tarsi I–IV, distoventral porose area on tibiae I–IV and dorsoparaxial porose area on femora I–IV and on trochanters III, IV well observable. Formulas of leg setation and solenidia: I (1–4–2–4–19) [1–2–2], II (1–4–2–4–15) [1–1–2], III (2–3–1–3–15) [1–1–0], IV (1–2–2–3–12) [0–1–0];

homology of setae and solenidia indicated in Table 1 ; seta s eupathidial on tarsus I.

Remarks — In having medium-sized body (about 450), pointed rostrum, short cusp on the lamella, short and globose bothridial seta, rounded notogastral porose areas, and 14 pairs of short, barbed notogastral setae, Z. birhanensis n. sp. is similar to Z. josefstaryi Ermilov and Rybalov, 2013 from Ethiopia. The new species can be distinguished from the latter by the morphology of the rostrum (with triangular medial mucro versus mucro absent), the length of the interlamellar seta (distinctly shorter than prodorsum, and not longer than rostral and lamellar setae versus as long as prodorsum or longer, and distinctly longer than rostral and lamellar setae), the presence of five pairs (versus four pairs) of notogastral porose areas, the morphology and lengths of notogastral setae (slightly dilated in median part, similar in length versus setiform, c 1, c 2, da, la distinctly longer than others), and the leg setation (femora I, II with four setae, l″ absent; genu I with two setae, v′ absent versus femora I, II with five setae, l″

present; genu I with three setae, v′ present).

Etymology — The species name birhanensis refers to vicinities of the place of origin,

Debre Birhan.

Figures

Figure 1 Zygoribatula birhanensisn. sp., adult (gnathosoma and legs omitted): a – dorsal view; b – ventral view; c – right lateral view. Scale bar 100 μm.

Figure 2 Zygoribatula birhanensisn. sp., adult: a – posterior view; b – subcapitulum, ventral view; c – palp, left, paraxial view; d – chelicera, left, paraxial view; e – leg I, right, antiaxial view; f – leg II (trochanter omitted), left, antiaxial view; g – leg III, left, antiaxial view; h – leg IV, left, antiaxial view. Scale bars 100 μm (a), 50 μm (e–h), 20 μm (b, d), 10 μm (c).